fix(angular): ensure table options updates are not missed during first mount window - #6534

The mechanism here is solid. Wrapping _options in computed() is what makes the previousOptions === currentOptions reference check meaningful in the first place, calling the raw factory twice always returns two different object literals, so without the memoization the comparison would never be equal and every effect run would apply. With computed(), a real signal change is what produces a new reference, so the effect's very first run can now tell "options actually changed since I captured the initial snapshot" from "nothing changed, this is just the effect settling," instead of unconditionally skipping the first run like isMount did. Traced the timeline in #6530 and this correctly handles the specific race described there, an update that lands in the gap between construction and the effect's first flush is no longer silently dropped.

Worth being precise about scope though, since the changeset and the linked issue don't quite line up. #6530 describes two problems: the primary one is lazySignalInitializer.ts's queueMicrotask eager-init firing before Angular's input bindings are applied, throwing an uncaught NG0950 in test environments with an async beforeEach. The isMount swallow is called out as a secondary issue, one that only surfaces once you work around the first one. This PR only touches injectTable.ts, lazySignalInitializer.ts isn't part of the diff, so it fixes proposal (3) from the issue but not proposal (1). The reported symptom, the uncaught NG0950 in TestBed suites, is still there after this merges. Worth linking as "part of #6530" rather than "closes #6530", or the eager-init half is going to look resolved when it isn't.